This paper analyzes the influence of distributed generation on electric distribution grid. In theoretical part of paper, influence of different distributed sources on distribution grid are described. In practical part of paper, influence of connecting biomass power plant with total installed power of 800 kVA on distribution grid is analyzed using Neplan software. 20 kV, 10 kV and 0.4 kV distribution grid model is made. There has been shown impact of biomass power plant on power flow, power losses, short circuit failures, transient stability and power quality.